Suggestion: Transmogs for cross-armor type

Would it be possible to implement the ability to learn transmogs for different armor types? For example, playing on a Plate character can learn transmogs for Cloth or Leather when they are looted. And then logging over to a Cloth or Leather character later will already have those appearances unlocked? That way you don't have to run a dungeon on 4 different characters of 4 different armor types to get all of the appearances.

Or playing on a Cloth character can still unlock the appearances of Plate armor in the collection upon looting the item. Point is, no matter what armor type the player is, if they could be able to unlock appearances for any armor type.

Instead of only Plate-->Plate, Mail-->Mail, Leather-->Leather, Cloth-->Cloth.

Maybe this could be done via a setting in the config for people to turn on/off if they didn't want it?

No files, tests, or entry points are named. Start by locating the armor-type eligibility and appearance-unlock flow triggered when an item is looted, then determine how unlocked appearances are shared across characters and whether the proposed behavior should be controlled by configuration; done means cross-armor appearances unlock and remain available as described.

Written by the indexing model from the issue text.